FORT WAYNE, Ind. — The Club for Growth has made a name for itself trying to unseat GOP incumbents.

But this year, with its 2010 winners up for re-election, the conservative outside group is playing defense , largely conserving its resources for open-seat opportunities in which it thinks it can make a difference.

Indiana state Sen. Jim Banks has the Club for Growth's backing in his race to replace Rep. Marlin Stutzman. (Meredith Dake-O'Connor/CQ Roll Call file photo)

Indiana’s presidential primary is poised to play a critical role in whether Donald Trump can secure a majority of delegates before the Republican convention. But the Hoosier State is also hosting competitive primary races for the Senate and two open congressional seats on May 3.

As GOP Reps. Marlin Stutzman and Todd Young battle in the Senate primary to replace Republican Dan Coats, there are competitive primaries to replace them in the House.